[Gmsh] Error: Cannot reparametrize a mesh node in high order meshing

[Christophe Geuzaine]

> On 24 Jun 2020, at 10:38, Mathias Scheunert <mathias.scheunert at mailserver.tu-freiberg.de> wrote:
> 
> Dear developers and users,
> 
> 
> 
> *** The goal
> 
> we want to do some finite element convergence studies on a given set of models.
> 
> These typically consist of large volumes containing small 'anomalies', i.e. volumes.
> 
> (Please note the attached MWE)
> 
> *** The problem
> 
> In order to ensure valid boundary conditions we need to enlarge the surrounding volume, leading to huge contrasts between the sizes of the involved volumes.
> 
> Using Gmsh 'RefineMesh;' will throw the above mentioned error.
> 
> -> Please try using line 6 instead of line 5 in the MWE.
> 
> 
> 
> What does that error message mean and how could we deal with that?

OpenCASCADE does not seem to appreciate the large aspect ratio during interpolation. As a workaround, set

Mesh.SecondOrderLinear = 1;

which will create the refinement by linear interpolation.

(Note that if you increase domain_r further to 100000000, OpenCASCADE simply seem to bail out...)

Christophe

> 
> 
> Best regards,
> 
> Mathias
> 
> 
> 
> ps: We are using Gmsh 4.5.6
> 
> -- 
> Dr. Mathias Scheunert
> Institute of Geophysics and Geoinformatics, TU Bergakademie Freiberg
> Gustav-Zeuner-Str. 12, D-09596 Freiberg
> Tel.: +493731393630 
> 
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— 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine